This invention involves no federally sponsored research or development.
This invention relates to regulated power supplies.
It is an important object of the invention to provide a high power partially regulated power supply using line frequency switching circuitry and having low switching loss and thermal protection.
According to the invention, a power supply includes a capacitor, having a first terminal and a second terminal, for storing DC charge. The power supply also includes first and second line input terminals for connecting to a source of AC line current, the AC line current having an AC line voltage, a transformer, coupled to the first and second line input terminals, for transforming the AC line voltage to a reduced AC voltage, a rectifier, coupled to the transformer, for rectifying the reduced AC voltage to rectified AC, the rectified AC having a voltage waveform having a rising edge, a falling edge, and a peak. The power supply also includes charging circuitry, coupling the rectifier and the capacitor, for charging the capacitor to a nominal DC output voltage. The power supply is constructed and arranged so that the charging circuitry charges the capacitor during an interval during the rising edge and during an interval during the falling edge, and so that the charging circuitry does not charge the capacitor at the peak.
In another aspect of the invention, a power supply, includes a first, second, and third output terminal and first and second line input terminals for connecting to a source of AC line current, the AC line current having an AC line voltage. The power supply further includes a transformer, coupled to the first and second line input terminals, for transforming the AC line voltage to a reduced AC voltage; a rectifier, coupled to the transformer, for rectifying the reduced AC voltage to rectified AC; and charging circuitry, for charging the first, second, and third output terminals to a first, second, and third electrical potential, respectively, so a potential difference between the first potential and the second potential is less than a potential difference between the first potential and the third potential. The charging circuitry includes a single switch.
In still another aspect of the invention, a power supply includes a capacitor, having a first terminal and a second terminal, for storing DC charge. The power supply also includes first and second line input terminals for connecting to a source of AC line current, the AC line current having an AC line voltage, a transformer, coupled to the first and second line input terminals, for transforming the AC line voltage to a reduced AC voltage, a rectifier, coupled to the transformer, for rectifying the reduced AC voltage to rectified AC, the rectified AC having a voltage waveform having a rising edge, a falling edge, and a peak. The power supply also includes charging circuitry, coupling the rectifier and the capacitor, for charging the capacitor to a nominal DC output voltage. The power supply is constructed and arranged so that the charging circuitry charges the capacitor twice during each rectified AC cycle.
Other features, objects, and advantages will become apparent from the following detailed description, which refers to the accompanying drawing in which: